5G PRACH Time-Shifting to Reduce Sector Interference
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Solution Overview
Problem
In 5G networks, traditional PRACH configuration methods lead to interference and preamble collisions due to the use of the same PRACH configuration index across sectors, resulting in decreased preamble success rates and increased latency.
Innovation Solution
Implementing a PRACH configuration system that utilizes the same root sequence index across sectors but employs time or frequency shifts for each preamble to avoid collisions and interference, allowing multiple UEs to send preambles at different times or frequencies, thereby reducing interference and improving success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same PRACH configuration index is used across sectors, then configuration simplicity is maintained, but interference and preamble collisions increase
Solution Approach 1:
The patent introduces a new dimension (time domain offset) to the PRACH configuration to differentiate preambles across sectors. Instead of using different root sequence indexes, the system applies time domain offsets to shift preamble transmission times, allowing the same root sequence to be used across sectors without causing collisions. This dimensional change resolves the contradiction by maintaining configuration simplicity while eliminating interference.
Solution Approach 2:
The patent changes the parameter used for preamble differentiation from root sequence index to time domain offset. By modifying this parameter, the system enables multiple sectors to use the same root sequence while transmitting preambles at different times, thereby reducing collisions and improving preamble success rates without increasing configuration complexity.
2Ease of operation
If traditional PRACH configuration is used, then implementation simplicity is maintained, but latency increases due to preamble collisions
Solution Approach 1:
The patent adds a time domain offset parameter to the existing PRACH configuration, creating a new dimension for preamble differentiation. This allows the system to maintain implementation simplicity by reusing existing root sequences while introducing time shifts to reduce collisions and latency, achieving both goals simultaneously.
3Reliability
If different root sequence indexes are used across sectors, then interference is reduced, but configuration complexity increases
Solution Approach 1:
Instead of using different root sequence indexes to differentiate sectors (the traditional approach), the patent inverts the strategy by using the same root sequence index across sectors and differentiating them through time domain offsets. This inversion simplifies configuration while maintaining PRACH performance by avoiding collisions through time separation.
Solution Approach 2:
The patent changes the differentiation parameter from root sequence index to time domain offset. This parameter change allows the system to achieve interference reduction without increasing configuration complexity, as the time offsets can be applied to existing sequences without requiring additional sequence generation or management.
Data Source
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AI summary
Systems and methods for enhanced PRACH 5G configuration by preventing interference with signal transmission. One such method includes: implementing a PRACH configuration in which the same root sequence index (RSI) is utilized across the sectors of the site, implementing the PRACH configuration in which a time shift is utilized for each preamble that provides each preamble with its own time slot, enabling multiple UEs to each send a preamble that is time shifted to arrive at the gNB at different times and avoid a RAPID (Random Access Preamble Identifier) mismatch, and receiving preambles that are frequency shifted and reducing PRACH interference among different sectors that causes a degradation of PRACH performance using shifts in time domain.